40. A lot of it is increased diagnosis, judging from my own experience

I've had Crohns since I was 5, but wasn't diagnosed till I was 16, due to most of the medical profession not thinking that kids could have it. Nowadays, children are diagnosed much more promptly.

However, increased poverty and its resulting poor diet could be aggravating the situation. So might concentrated milk fat - but more research needs to be done. There's no doubt that in some people dairy products, fat, or both can aggravate the symptoms of IBD, even if they don't cause it in the first place.